摘要
1970年1月5日云南通海发生了MS7.7地震,震后发生了多次MS>5.0的强余震。文中计算了1970年通海7.7级大地震后,主震分别在5次强余震破裂面上诱发的库仑破裂应力变化(ΔCFS)。结果表明,有4次强余震发生在库仑破裂应力增加(ΔCFS>0)的地区,增加的范围为10-2～10-1MPa;有1次强余震按2种震源机制解结果给出的破裂面计算,得到2种结果,分别发生在库仑破裂应力变化为正和在库仑破裂应力变化为负的地区。研究结果表明,主震位错产生的库仑破裂应力变化可能是1970年通海7.7级大地震强余震活动的重要原因。
The Tonghai great earthquake occurred on Jan. 5, 1970 in Yunnan Province. After the main shock, several large aftershocks (M_S>5.0) occurred. Calculations of the change in Coulomb failure stress on aftershock failure plane reveal that 4 events among 5 large aftershocks occurred in areas with ΔCFS>0 (10^(-2)～10^(-1) MPa); There are two contrary results for one aftershock due to two different focal mechanism, this aftershock occurred in areas with ΔCFS>0 and ΔCFS<0. It is concluded that the permanent fault displacement due to the main shock is the main causation of activity of large aftershocks.
出处
《地震》
CSCD
北大核心
2004年第2期38-46,共9页
Earthquake
基金
十五"国家科技攻关项目(2001BA601B02 02 04)
中国 希腊国际地震合作研究项目
地震科学联合基金项目(103073)
关键词
余震
地震触发
库仑破裂应力
震源机制
Earthquake triggering
Coulomb failure stress
Tonghai great earthquake
